Siblings
by Repiece
Summary: Chifuyu doesn't understand this feeling she gets whenever she see her younger brother surrounded by the other girls.  So, she decides to confront him about his feelings towards them and then it suddenly leads to something more.  Rated M!


Disclaimer: I do not own anything related which includes the characters of Infinite Stratos.

**Rated M for a Reason. Contains Incest so if you don't like it, don't read it! You have been warned.**

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><p><strong>Siblings<strong>

Chifuyu Orimura was never one to care much about other people's love life. She was an intimidating figure who was feared, but also respected by everyone at IS Academy. However, no matter how much she tried to block it in her mind and ignore it, she couldn't help notice all these girls trying to grab his attention.

Even now, as she stood in front of the class, that she noticed many of the girls eyes her younger brother from time to time. She narrowed her eyes at her brother. She watched him try to keep up with the lesson, but she could tell that he was having a hard time, being the first male IS user in history only made it harder.

Despite all that, it amazed her how dense he was. She couldn't believe that he wasn't able to notice the girls trying to get his attention. It was so obvious, but he was, in her mind an idiot when it came to love.

Later that day, Chifuyu walked through the dorms to make sure none of the students were doing anything inappropriate. She knew that the students wouldn't try to do anything like that, but it still didn't hurt to look. After walking for an hour or so, she saw her younger brother with two of his classmates. Houki Shinonono and Charlotte Dunoa.

Looking at the two, she couldn't help but frown. She didn't know why she did, but she did so. Looking at the two girls, she noticed that they were trying to flirt with him, but as usual, Ichika didn't even notice what the two were doing. After watching them for a few more seconds, she closed her eyes and made her way toward them.

"Ah, Chifuyu-nee!" Ichika was surprised that his older sister was inside the dorms.

"That's Orimura-sensei to you." She replied for about the hundredth time.

"R-Right..." Ichika chuckled. "What are you doing here, anyway?"

"I'm making sure none of you are doing anything stupid." She replied, crossing her arms under her cleavage. The three all chuckled nervously and sweat dropped at her reply.

"Oh no!" Charlotte suddenly screamed as they looked at her in confusion.

"What is it, Char?" Ichika asked.

"I forgot that I'm supposed to meet somebody at the library today. I'll see you later, Ichika!" Charlotte told him as she ran off toward the library. Ichika waved goodbye as he turned back around. His eyes met with his sister and suddenly felt a cold shiver run down her spine at the way she looked at him. She then closed her eyes.

"Ichika, come with me." She told him sternly as she walked past the two.

"Huh? Why?" He asked, but when she turned her head around to look at him over her shoulder, he quickly did as he was told and followed right behind her, leaving Houki behind as she raised an eyebrow at the sudden request from the stern and strict Chifuyu.

After walking for about ten minutes, the two Orimura siblings arrived in front of Chifuyu's room as she opened the door. Ichika was surprised that his sister would take him back to her room as she left the door open. "Get in." She told him from inside as he did as he was told and entered her room, closing the door behind him.

He looked around and noticed that her room was similar to how the student's dorm rooms looked. The only thing that was different in her room, was the one large bed, instead of the regular two bed dorm room. "Um, why am I here, Chifuyu-nee?" He asked his sister, who came out of the kitchen.

"I told you to call me, Orimura-sensei." She replied as she walked up to him.

"O-Okay, why am I here, Orimura-sensei?" He asked again as he nervously looked at her, blushing at how close she was to him.

"Tell me, Ichika...what do you think about them?" Chifuyu asked, but only got a confused look from her younger brother.

"Them?" He asked.

"The girls you always hang out. Shinonono, Alcott, and the others?" She simplified her question as Ichika rubbed the back of his head.

"W-Well, I...um..." He tried to find the right words to say as his cheeks were red from his blush. "I...I don't know how to answer that...I am...I like them...I do...they're fun to hang out and..."

Chifuyu was getting annoyed by his answer. She would think that he would answer properly when he talked about his friends, but she had to admit, she did find him cute the way he was blushing like that. Chifuyu couldn't believe what she was thinking. She was supposed to not have thoughts like this. She was supposed to be stand tall with authority and not think about her brother as being cute. She was supposed to be a role model for the girls of the Academy.

"Orimura-sensei..." Ichika's sister was snapped from her thoughts when she heard him calling her name.

"What is it?" She asked with her stern voice.

"I was wondering why are you asking me such a question?" He asked.

"Because I..." Chifuyu stopped when she realized she didn't know the answer herself. Why was she asking him about her other students. It just wasn't like her. She tried to think of a reason, but no matter how much she thought she couldn't come up with one. "No reason..." She decided to answer with that and closed her eyes.

"I see..." Ichika was confused by her answer.

"Ne..." He looked at her and noticed that she had a faint blush on her cheeks. He was surprised to see his sister look like this, though even he knew she had some what of a girly side to her. "...did you ever do 'that' with any of them?"

"That?" He asked confused by what she was talking about. Chifuyu looked at him before looking away. She didn't know why she asked such a question, but her mouth moved on it's own. Now there was no backing out of this, so she went on with her question.

"I mean...s-s-sex..." Her face became a deep shad of red at her clarification and it was the same with her younger brother.

"W-W-What? W-Why are you asking me such a thing? Of course, I didn't!" He shouted, waving his hands in front of him.

"I see..." She replied, looking away. She suddenly sighed in relief and that both surprised her and Ichika.

"Orimura-sensei..." He muttered her name and she quickly turned around to hide her extremely red face.

"It's nothing!" She shouted, but her voice clearly showed that she was nervous.

"Chifuyu-nee...did you ever...?" He asked suddenly and his sister quickly turned around and denied it.

"Of course not! What kind of girl do you think I am? And call me Orimura-sensei!" She shouted like a high school girl. Ichika felt relieved that his sister didn't do it either. He wasn't sure why he felt relieved, but he had to admit, the way she reacted made her look very cute. Ichika couldn't believe what he was thinking! This was his sister he was talking about. The same sister who he owed his own life to. He looked at her and couldn't help his eyes as they wandered down her body to look at all her curves. He blushed when his eyes set upon her chest and suddenly felt a weird feeling all over his body. Chifuyu noticed his stare. "W-What?"

Ichika jumped in surprise and started waving his hands again as his face became red again. "N-Nothing...!"

"Don't lie to me! What were you thinking about?" She demanded an answer as she walked toward him. Ichika felt nervous the closer she got and started to back away until he couldn't go any farther. "Well?"

"I...um..." He blushed at how close she was to him. 'Crap! What do I say? I can't just say that I was checking her out! She's my sister! Damn it!' He looked at her and for some reason, his eyes couldn't help look at her lips, seeing the light pink lipstick she wore. He suddenly felt a strange thing in his body that he was trying to fight off, but it was winning. Without realizing what he did, or the consequences behind it, he suddenly kissed his older sister on the lips.

Chifuyu was shocked beyond belief at what he was doing. He was kissing her. Her younger brother was actually kissing her. Not only that, but he also took her very first kiss! She couldn't even comprehend what he was thinking when he decided on doing this. They were siblings and yet here they were kissing each other like it was natural for them. She didn't even know why she wasn't pulling away from the kiss. For some strange reason, her body wasn't pulling away, despite the protests her mind was telling her. She knew this was wrong beyond so many levels, but her body just wouldn't pull away.

Ichika knew he was going to die after doing what he did. He kissed his own sister. This was considered taboo even in Japan. He knew after this, he would probably be left a bloody pulp on the floor. However, it was strange. Chifuyu wasn't pulling away. It certainly did surprise him. After all, knowing his sister, she would have pushed him away and then beat him down with whatever was nearby until he lost consciousness. Yet, she wasn't doing that. It was almost like she was returning the kiss. She wasn't doing anything per say, but it felt like she was kissing him back.

Ichika was the one to pull away and Chifuyu had to thank him because she knew she wasn't going to be the one to do it. Both siblings looked at each other, with flushed faces and heavy breathing. Chifuyu had to admit that her younger brother was a good kisser, but the voice in her head kept telling her that this was wrong. However, she just couldn't help miss the feeling of his lips against hers. She actually wanted more.

Ichika was also surprised that she didn't back away when he kissed her so unexpectedly. It was confusing him, but he felt the urge to kiss her again. The feeling of his older sister's lips against his was like nothing her ever tasted before. The lipstick she wore made the kiss even better. Both looked at each other, thinking the same thing. They wanted to do it again. So without any warning, the two locked lips again and pressed their bodies to each other.

Ichika moved his arms to her hips and felt her move her own arms to the back of his neck, and pulling him deeper into the kiss. The feelings the Orimura siblings were feeling was like nothing they ever felt before. The kiss they shared was filling them with a tingling sensation that neither have felt before or even known about. Both started to use their tongues and deepening the kiss. Their tongues danced in the open space between each others lips and their bodies felt so good against each other.

Ichika's face became red when he felt her breasts pressing against his chest. Chifuyu 's face became the same when she felt something between her legs pressing against them and she could only think of one thing that this 'thing' could be. The thought of her brother being turned on by her kissing never entered her mind. However, she couldn't complain as the area in between her legs was getting wet from her getting turned on by her kissing Ichika.

Both siblings separated and then stared at each other. "I-Ichika..." She moaned his name. Ichika was surprised that she said his name in that kind of manner. Never once did he hear his sister speak like that to anyone. It actually turned him on even more. He then kissed her again and without knowing what he was doing, he pushed her down to the bed. They continued to kiss even while Ichika pushed her down and he started to roam his hands all over her body.

The two of them knew what they were doing, but at this point, the thoughts they had about how bad this situation was were gone and instead were replaced with thoughts that could only come from their raging hormones. He pulled away from the kiss and then rose with the support of his arms and looked down at his sister. Never before has he seen his sister like this and he had to be honest with himself, she was the most beautiful person he had ever seen.

"Chifuyu-nee...you look so..." He couldn't finish the sentence because he was too captivated by how she looked at this moment.

"W-What?" She asked, blushing and looking away from him.

"S-Sorry...I was just speechless because of how beautiful you look..." He revealed to her and her blush got to a deep shade of red that Ichika never saw before.

"B-Baka..." She said, but with a smile and then kissed him. Ichika was surprised that she kissed him first, but settled down a second later. "Ichika..." She moaned during the kiss before pulling away. She raised herself so that she sat on the bed, Ichika only a few inches away from her. Ichika watched his older sister as she began to slowly take off her clothes in front of him, making him blush the same color as Chifuyu's face was.

"C-Chifuyu-nee..." He whispered, but she silenced him with a finger to his lips.

"Be quiet..." She told him. She didn't say anything else before she continued to undress herself. Ichika's eyes widened as she tossed her clothes and bra to the floor and he saw her naked chest, her arm covering her large mounds that even he had eyed from time to time. He looked away from her chest and up to her face as she saw looking away to the side, avoiding eye contact with him.

"Chifuyu-nee..." Ichika whispered her name and then smiled at his older sister. He put a hand to her face and turned her head so that she would look at him and then he kissed her. Chifuyu closed her eyes and returned the kiss as he again lowered her down to the bed. After he pulled away from the kiss, he started to kiss her on the neck, making her moan.

"I-Ichika..." He loved the way she moaned his name and only continued to kiss her neck and then down to her collarbone. He continued to head downward until he reached her arm that covered her breasts. He looked up at her and smiled before grabbing her arm and moving it down to her side. When he saw her breasts, he was left speechless. They were perfect. He took the knowledge he learned from many magazines and websites and grabbed her breasts and then giving each a soft squeeze. "Aah!" His sister let out a scream.

"S-Sorry..." He apologized thinking he hurt her.

"No...d-don't apologize...that felt good..." She moaned. Ichika nodded and gave her mounds another squeeze. Again she screamed and Ichika didn't stop this time. He continued to give his sister's breasts soft squeezes until he had the urge to taste them. He lowered himself down and captured on of her breasts in his mouth. Chifuyu let out another scream at the feeling of his warm mouth against her breasts. Liking the noise she made, he continued to suck on her breast.

Chifuyu was surprised at how good her younger brother was making her feel. She knew he told her that he never did this before, but he was incredible. He was making her feel like she never felt before. She didn't even feel this good when she did it by herself. She felt the hand on her other breast begin to move and it doubled the pleasure she was feeling. It felt so good that she could feel herself coming close to her first orgasm.

When he removed his mouth from her breast, she felt disappointed at the loss of the warmth and pleasure, but they soon returned as he placed his mouth over her other breast and his hand on the other. The feeling in the pit of her stomach was increasing every second Ichika's mouth was on her breast. She knew it wasn't long until she would reach her orgasm. When her brother started to flick his tongue against her erect nipples, the feeling only intensified and a few seconds later, she let out a scream and felt herself climax.

Ichika quickly pulled up at the sound of her scream and looked at her in surprise. "W-What's wrong?" He asked. His sister didn't respond as she was too busy trying to catch her breath. He wasn't sure what was going on until he looked at her groin area and saw the sheets underneath her were wet. "No way...Chifuyu-nee...did you just..." He tried asking, but stopped when he saw how embarrassed she looked. He smiled at her before moving up and kissing her on the lips.

"Ichika..." She moaned as he lifted himself up. He smiled at her and then raised himself so that he sat just in front of her legs and started taking off her skirt and stockings. She blushed immensely when he started and when he was finally able to get rid of both articles of clothing, leaving her only with her black panties. However, not even those stayed on long and he took them off as well. Ichika's eyes widened in amazement at his first sight of a woman's private part and he just couldn't keep his eyes off of it. "S-Stop staring like that...i-it's embarrassing..." Ichika looked away from her pussy and at his sister.

"Sorry...but right now...you look even more beautiful than ever...Chufuyu-nee..." She blushed heavily at his compliment and looked away to avoid further embarrassment. He smiled at the way she acted and without her knowing, he lowered himself and then took a lick of the tongue against her vagina. She let out a loud moan the contact between his tongue and her sacred place.

"I-Ichika..." She said his name in surprise, but he gave her vagina another lick. Chifuyu let out another loud moan and due to his liking of the way she moaned, continued to taste her. His older sister began to writhe around as he attacked her vagina. Chifuyu couldn't believe how good her brother was. Now she really questioned whether he had any experiences in doing this. She clenched the sheets of her bed as he continued to lick her pussy.

The feeling of another orgasm soon came and she was just baffled at the fact that she was going to climax for a second time by her own brother. Even when she masturbated, she could never feel as good as she does now. Ichika loved the taste of his sister. He was just as surprised as she was at how good he was doing. He didn't even know if he could pleasure anyone let alone his own sister. However, from the moans and screams she was emitting, he knew he was doing a good job.

Chifuyu couldn't hold on much longer before she came for the second time. Ichika was shocked when he felt her juices begin to spray out of her private area and splash on his face. However, he soon got over it and covered his mouth over her vagina to taste more of his sister. When she settled down, Ichika lifted his head and leaned forward to kiss her. Chifuyu could feel the taste of herself against her brother's lips as they deepened the kiss. When they pulled away, Chifuyu decided that it was her turn to pleasure her younger sibling.

So, she put her hands on his shoulders and pushed him down with her on top of him. Ichika looked up at his naked sister and was mesmerized by the way she looked right now. "C-Chifuyu-nee..." He whispered her name and watched as she lowered herself to kiss him. She started to move her hands to unbutton his uniform until his chest was exposed. She blushed at the sight of his naked body. He wasn't muscular, but she just couldn't keep her eyes off his chest. However, they weren't her goals as she moved her hands down and started removing his pants. Ichika blushed in embarrassment as he saw his erection sticking upward.

Chifuyu blushed at the sight of how big his penis was. She didn't expect his penis to be this big. She was afraid to see the true form of the beast under his boxers, but mustered up the courage and slowly removed his boxers. She watched as his penis was now exposed as Ichika felt embarrassed that his sister saw his cock. Chifuyu then moved her hand to grab his penis and at her touch, Ichika groaned. Chifuyu was surprised by his reaction, but knew that it meant that it was a good reaction and so began to move her hand in an up and down motion. "Ahhh! Chifuyu-nee..." He groaned again and Chifuyu was pleased by his reaction. She felt the pre-cum against her skin and began wondering what it tasted like.

Taking a big gulp, she leaned forward and then licked the tip. She was rewarded with another groan and moan from her brother. The taste wasn't all that bad. It was a little salty, but she didn't mind it. So, she gave it another lick and before she knew, she was licking his erection up and down. "Ahh! Chifuyu-nee...it feels so good..." He moaned in ecstasy. She was happy that he said that and then decided to take the next bold step and suddenly engulfed his shaft in her mouth. Ichika couldn't believe how good the feeling of his penis inside his sister's mouth was. It was better than anything he ever felt before. The feeling of her tongue moving around his shaft as she bobbed her head up and down was incredible.

Soon, Ichika felt his first orgasm coming and he looked at his sister to warn her. "C-Chifuyu-nee...I'm going to..." He groaned, but couldn't finish the sentence as he felt his shaft getting ready to burst. After a bob and a flick of the tongue, he came. Chifuyu's eyes widened when she felt her brother's sperm shoot from his shaft and into her mouth. She was surprised, but didn't let go of his cock and swallowed every ounce of his seed that came out. When she felt his penis no longer twitch, she removed her mouth and then looked at her younger brother.

"Ichika..." She whispered his name before getting up and hovering above him. His eyes widened when he saw her doing this and knew what she was going to do next.

"Chifuyu-nee...are you sure? I mean..." He told her and then she smiled at him. He never saw such a smile on her face before and he felt like he was in a trance. Whatever he wanted to tell her, he immediately forgot and just allowed her to do what she wanted.

"Ichika..." She moaned again and then grabbed his penis. He watched as she moved her hand up and down to get his shaft erected again and when she did, she began lowering herself down. When she felt the tip touch against her vagina, she felt a shiver run through her body. Ichika felt the same way. She then lowered herself again and felt his penis enter her. The warm feeling they both felt was incredible and it only made Chifuyu continue lowering herself. Ichika couldn't believe how tight his sister was. He was surprised, but then again, she was a virgin. It then hit him. She was a virgin, which meant that it was going to hurt her.

"Chifuyu-nee..." He tried to warn her, but it was too late as he felt himself pierce through a wall and his sister letting out a painful scream. "Ah! Chifuyu-nee!" He shouted, scared that he hurt his sister.

"It's okay..." She suddenly told him, opening one of her eyes to look at him. "I could handle it..." The supposedly former 'White Knight' told him and then closed her eyes again. She waited for the pain to pass away before doing anything else. She could feel blood escaping from her vagina, but she didn't care and waited patiently. When the pain was all gone, she started moving. She slowly moved up and then back down and both siblings felt incredible pleasure.

"Chifuyu-nee..." Ichika groaned as he watched his sister move above him. He was in a trance at the way she moved. Her breasts bounced up and down with every movement she made and it only made him want to touch them. So, he did. He raised his arms and took her mounds in his hands. His sister let out a loud moan at the touch of his hands against her breasts and moaned even louder when he flicked her nipples with his fingers.

"I-Ichika..." She moaned his name again. Ichika started pushing his hips up to match the rhythm they were in and it caused his shaft to make it all the way to her womb. "Ichika...your hitting my..." She moaned and stopped herself from completing the statement to avoid embarrassment. Even though she stopped, Ichika knew what she was going to say, after all he could feel him doing it.

They decided to switch positions as Ichika moved her until he was above her and started to pound into her. He lowered himself to kiss her, while continuing to penetrate his sister. Chifuyu wrapped her legs around his waist while she clutched the bed sheets as tightly as she could. The pleasure they were feeling in the missionary position was even better. The sound of their skin smacking against each other was heard throughout the room like an echo, but their moans surpassed those sounds.

Then, the time for the climaxes was approaching. For Ichika, this would be his second while for the older Orimura sibling, this would be her third. Ichika's thrust began to quicken in pace as the moans became louder with each one. Both were feeling their orgasms quickly coming and were soon going to be released. "Chifuyu-nee...I'm about to cum..." He warned her to make sure she let go of him before cumming inside of her.

"M-Me too..." She moaned along with him. They kissed again before his thrusts began getting faster.

"Chifuyu-nee...I'm about to cum so let me go..." He told her. However she didn't. "Chifuyu-nee..." He warned her again, but she didn't do it. He was about to warn her for a third time, but it was too late, he came. Ichika arched his back and thrust in as deep as he could into her as he his penis twitched and released his seed inside of her. Chifuyu screamed at the feeling of his warm cum entering her womb as she reached her own orgasm, her vaginal walls squeezing his erection. This caused more spurts of his seed to enter her.

When he finished releasing his seed, Chifuyu's legs let go of him and he fell to the side on his back. Both siblings panted for air as they looked up at the ceiling. They were exhausted from the sex they were involved in as they both knew the consequences of their actions. "I-Ichika..." Chifuyu moaned his name.

"Chifuyu-nee...I'm sorry...I came inside you..." He apologized as they turned their heads to look at each other. She then smiled at him.

"Don't worry...I'm on the pill and today happens to be my safe day..." Ichika let out a sigh of relief at that and smiled back at her.

"I see..." He said and then closed his eyes. Chifuyu smiled warmly at her brother before rolling to her side and pressing him toward her. She then heard him snore and giggled at her sleeping brother.

"I'm sorry...Ichika...I lied..." She said before she too fell asleep. The two Orimura siblings both were now asleep in each others arms. Both knew what they did, but it was so incredible that they couldn't stop. Who would have thought that their first times would be with each other. Chifuyu didn't regret this decision. She knew that Ichika didn't as well and knew that their relationship got closer to what it was a couple of minutes ago. She was happy about that and was able to sleep calmly, despite the consequences she knew she would have to deal with. However, she didn't care and just slept. She did know this...she was happy that her first time, was with her own brother, her smiling being the proof of that.

**The End**

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><p><strong>Author Notes:<strong> Well, here you guys go! My first one-shot of the new year! Hope you guys liked it!


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